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Electro-surgical forceps have a pair of resilient blades or arms that are used for grasping and coagulating tissue. The forceps may be monopolar or bipolar. In monopolar forceps, the blades are welded or otherwise joined to form an electrode in electrical communication with an electrical generator. Current flows from the active electrode through the patient""s tissue to a dispersive electrode in contact with the patient""s skin (which may be at some distance from the forceps) and back to the generator. In bipolar forceps, each blade of the pair comprises an electrode in communication with an electrical generator. Current flows from one blade through the tissue to the other blade.
In some instances, tissue may adhere or stick to the tips of the blades. If sticking occurs, the surgeon must pull on the forceps to release it from the tissue, possibly causing further bleeding and requiring that the forceps be cleaned. It is known to prevent or minimize such sticking of tissue to electrosurgical forceps by manufacturing the blades of the forceps from nickel. See, for example, U.S. Pat. No. 5,196,009. During high power operation, some eschar buildup and some sticking of the tissue to the tips still may occur.
Another known manner of preventing or minimizing sticking is to form the blades from a metal or metal alloy having a relatively high thermal conductivity, such as copper, that is able to transfer heat away from the tips of the blades. By keeping the tissue cooler, for example, below the boiling point of water, coagulation is able to occur without sticking of the tissue. See, for example, U.S. Pat. No. 4,492,231. Nickel is more biocompatible with human tissue than copper and is preferable for contact with tissue, as well as providing additional non-stick capabilities. Thus another known forceps provides blades formed of an inner layer of copper or copper alloy having a thickness sufficient to dissipate heat and an outer covering of a strong, biocompatible metal or metal alloy such as nickel metallurgically bonded to the copper layer. See U.S. Pat. Nos. 6,059,783 and 6,298,550, the disclosures of which are incorporated by reference herein.
The present invention provides an electro-surgical forceps having an outer plating covering the entire surface of the tines, from the tip to the cap. The plating material has a greater thermal conductivity and preferably also a greater electrical conductivity than the core material of the tines. In this manner, a thinner plating can be used than in prior art forceps that are plated only at the tips while still achieving sufficient heat reduction to prevent or minimize sticking of the tissue and eschar buildup.
More particularly, the forceps has a pair of tines, each tine being generally elongated and having a tip and an opposite end fixed within an insulating cap portion. At least one of the tines is electrically connected to at least one terminal within the cap portion. The tine is formed of a core comprising a metal layer formed of stainless steel, nickel or titanium. An outer plating covers the entire surface of the core. The outer plating is formed of a material having a thermal conductivity or an electrical conductivity greater than the core. Suitable outer plating materials include commercially pure silver, rhodium, gold, aluminum, palladium, tungsten, or nickel.
The plating thickness should be at least 0.001 inch to provide sufficient heat and/or electrical conductivity and wear resistance. The thickness should be no greater than 0.010 inch to minimize the amount of plating material needed. A suitable range of plating thickness is 0.004 inch to 0.008 inch. The plating is preferably formed by an electroplating process, although other plating processes may be used.